Jeff,

We just got the Gerbers loaded online. It should be all the project files. See here:

Let me know if this meets your needs.

Regards,

John

Hello, these are just the gerbers, someone on your team needs to use the project packager in altium and zip up the files. There is no schem or PCB file in the gerbers. Also the library is not included for footprints. If you can give me a name I can email. Thanks

Hello Jeff,

I am pursuing the original source for these files and will forward the files you need when we get them.

Regards,
Ulrich

Thanks for the help...

Hi Jeff,

Just to let you know that I haven't forgotten you, but I haven't received a reply from the source yet either.
I'll "ping" them again.

Regards,
Ulrich

Great thanks...and one more request

Also for the LM5023, I modified the circuit to get 28v out by changing the feedback loop. This works, but not under load. Webbench does not show this part at this time. May I have the spreasheeet that is usually with your parts, I must need to change some other value.
It does not appear the datasheet has all the calculations for the part.
I did not notice in another similar design, it was maxed at 24v. Please send the spreadsheet, as I need to get to 28v, or add a boost circuit. TPS43061 will work if required. I would prefer not to add this as creates extra cost.

thanks
jeffk

Hello Jeff,

The TI website page for this device does not show an Excel calculator to be available. This LM part came to TI through the acquisition of National Semiconductor some years back, and I don't think they made a calculator for it, but I do believe all the equations necessary for design are in the datasheet.

If you modified the EVM for 28V at the LMV431 regulator resistors only, then the circuit may be shutting down due to overvoltage at the QR input. The transformer is designed for a 19V output and the turns ratio to the auxiliary winding reflects that. Putting 28V at the output raises the Aux voltage by ~1.5x so the resistor values at QR must also be adjusted to accommodate this. See DS design equations to reset these.

Also, be careful of applying high voltage to the AC input. That turns ratio is also geared for 19V, so the reflected voltage is 1.5x higher than normal during flyback and may overstress the MOSFET at high line.
Also check the voltage margins of the output caps and aux caps rating. The 15-V clamp zener D5 on the VCC may be overstressed, too, because AUX voltage (VCC) goes up by 1.5x. It is there to protect the LM5023 from OV since it has a 16-V absolute maximum rating on VCC.

If you can redesign the transformer to match your voltage increase, you can avoid adding a boost circuit.

Regards,
Ulrich

Thanks for the response, I do have the a new transformer designed and soldered in...I forgot to tell you this. I did not change the QR circuit, I will review the DS calcs. I will check the D5 voltage also. More to follow on this. We still have an open action item with the Altium files for this design.
thanks for the help. Its almost working...

jeffk

status update on the Altium project please

Hello Jeff,

I'm sorry to report that the Altium files for the LM5023 EVM board are not available.  I've been informed that these files had been lost in a disk-crash some years back, and apparently they had not been backed up.  The information in the EVM product folder on the TI website is all the documentation that we have available for that project.  

New pcb artwork will have to be recreated from the Gerber files and from the schematic and images shown in the User Guide, or start a new project entirely from scratch.  I'm sorry that I don't have better news about this.

Regards,
Ulrich

thats to bad...ok, have created a detailed spreadsheet of all the formulas in excel. I do not see the formulas for the feedback network...R12, r14, r18,r21, r20....I want to get all this into this sheet. just finishing this design off now. Need a little more data, Please

Hello Jeff,

Resistors R18 and R21 form a resistor divider to scale down the output voltage to match the reference voltage of the LMV431 shunt regulator, which is 1.24 V. Neglecting the reference pin bias current, Vout = Vref(1+R18/R21). That gives you the ratio of the resistor values. If you choose Meg-ohms for the divider, the Vref bias current will affect Vout by raising it. To avoid this, set the total divider current to be more than, say, 100x the bias current, which is about 1.5uA typical, (3uA max). So Vout/(R18+R21) > 150uA. With these two equations you can solve for each value.

R14 is merely a signal-injection impedance for a network analyzer to measure the frequency response of the prototype power supply. This one is 10 ohms, but usually they are ~50R. In either case, they are neglected in the calculations.

The other components involved in loop compensation are R12, R20, C14, C16, an internal resistance at the COMP input, and the CTR of U2. These are used in more complex calculations which involve the control to output voltage transfer function of the power stage. I thought I found this function for the LM5023 and but seemed peculiar to me, so I asked around for another opinion and got a different function in a different notational format. I have to try and re-derive it and see if it matches one of the two candidates.

Before I can give you a set of equations to determine values for the loop compensation components I need to verify that the transfer function makes sense and is correct. This will take me some time, unfortunately, and it will be next week before I can provide this.

Regards,
Ulrich